While that precise address (perhaps unsurprisingly) is not turning up on a modern day Google Maps search, I did find the office of a registered building inspector/land surveyor named Katsuhiko Hatta in that exact vicinity (Azayashiki, Tosaki-cho, Okazaki City, Aichi Prefecture).
八田克彦事務所は、愛知県岡崎市にある土地家屋調査士で測量の品質と価格を高次元でバランスしてご提供しています。
www.hatta-office.com
There is also a company, 八田建設会社 (Hatta Construction), in the same general area:
愛知県岡崎市の八田建設株式会社です。お客様の「健康に暮らせる住まい」づくりの実現をお手伝いしています。健康住宅の八建(8ken)ホームページへようこそ。
Of course, there's no way to say for sure, but it certainly would not shock me if these were her relatives.